Electric-only and hybrid electric vehicles have become increasingly capable and increasingly popular in recent years, as rising fossil fuel prices and improved battery technologies level the cost and performance fields between the vehicle types. Indeed, while the range and acceleration of production-level electric vehicles have historically lagged behind those of their fuel-powered counterparts, this situation is rapidly changing as high-capacity battery technologies are optimized and commercialized.
Nonetheless, despite the increasing parity between electric vehicles and fuel-powered vehicles, there are numerous differences between the vehicle types that require different handling and operational procedures. For example, the voltage present in a fuel-powered vehicle is generally fairly low, e.g., 12 volts, with the exception of certain sheltered areas such as spark plugs and ignition-related capacitors and transformers. In contrast, the core power system in an electric, hybrid or extended range electric vehicle utilizes high voltage and current levels.
While these high voltages are beneficial in providing the efficiency and power levels required in electric vehicles, they may also pose a hazard to personnel in certain circumstances of misuse or inadvertent damage. For example, when an electric vehicle having a high voltage battery is involved in a collision or incident of sufficient severity to disturb the battery casing or battery connections and contacts, the high voltage of the battery may be exposed to personnel, such as emergency responders, via exposed wiring or charged surfaces.
Thus, first responders to vehicle incident scenes that a potential involve a high voltage hazard are required to first test the environment, i.e., frame, metal roadway items such as railings in contact with the vehicle, and so on, to ensure that there is no electrical hazard present. If an electrical hazard exists, the responders will adjust their rescue strategy to eliminate the hazard if possible and to avoid the hazard if elimination is not possible.
However, the considerable time spent determining the state of the vehicle and its environment detracts from the time available for rescuing or giving emergency care to any injured occupants of the vehicle or other personnel involved in the incident. Prompt care is especially important early in the response, so that any injuries may be stabilized and further injury or damage may be prevented.
It is an object in certain implementations of the invention to provide a system that quickly and efficiently apprises emergency responders and other personnel of the state of the onboard battery system, and in particular, informs responders as to whether a non-nominal condition exists. Although this is an object underlying certain implementations of the invention, it will be appreciated that the invention is not limited to systems that solve the problems noted herein. Moreover, the inventors have created the above body of information for the convenience of the reader and expressly disclaim all of the foregoing as prior art; the foregoing is a discussion of problems discovered and/or appreciated by the inventors, and is not an attempt to review or catalog the prior art.